Meade DSX Series Choosing an Eyepiece, DSX-90 Viewfinder, Screws 4 and 6, DSX-125EC Viewfinder

Telescope

Viewfinder Eyepiece

A. Not aligned

B. Aligned

Fig. 13: Aligning the viewfinder.

NEVER point the telescope directly at

or near the Sun at any time! Observing the Sun, even for the smallest fraction of a second, will result in instant and irre- versible eye damage, as well as physical damage to the tele- scope itself.

DSX-90 Viewfinder
					d
1. Remove the viewfinder by slightly
					c
unthreading the four alignment
screws (4 and 6, Fig. 12) and
slipping it out of the bracket.						e
2. Loosen the knurled		lock-ring	(2,
Fig. 12) located near the					DSX-125
viewfinder’s front lens cell (1, Fig.
12).	Unthread	this	ring			d
(counterclockwise, as seen from
the	eyepiece-end	of	the		b c	f
viewfinder) by several turns.
						g
3. Look through the viewfinder and					DSX-90
focus on a distant object. Slowly
rotate the front lens cell in one
				Fig. 12: The Viewfinder assembly. (1) Front lens cell; (2)
direction or the other, until the
object appears sharp. One or two				Knurled lock-ring (DSX-90) or focus ring (DSX-125); (3)
rotations of the lens may have a				Viewfinder eyepiece; (4) Front alignment screws (one not
				visible in photo); (5) Viewfinder bracket; (6) Rear alignment
significant effect on image focus.
				screws.

4.Lock the focus in place by

threading the knurled lock-ring clockwise up against the viewfinder’s lens cell.

5.Replace the viewfinder into the viewfinder bracket. Gently tighten the six alignment screws. Proceed with Aligning the Viewfinder.

DSX-125EC Viewfinder

Turn the focus ring (2, Fig. 12) at the base of the viewfinder eyepiece (3, Fig. 12) in either direction until a sharp focus is reached.

Aligning the Viewfinder:

It is recommended that you perform steps 1 through 4 of this procedure during the daytime and step 5 at night.

1.Loosen the tripod base lock knob (16, Fig. 1a) and the Altitude lock (B, Fig. 1b), by turning the lock about one turn counterclockwise, permitting the telescope to move freely on its axes.

2.If you have not already done so, place a low-power (e.g., 26mm) eyepiece in the eyepiece holder of the main telescope (2, Fig. 1d) and point the telescope at an easy-to-find land object (e.g., the top of a telephone pole). Turn the focuser knob (1, Fig. 1d) so that the image is sharply focused. Center the object precisely in the main telescope’s field of view.

3.Re-tighten the tripod base lock knob (16, Fig. 1a) and the Altitude lock (B, Fig. 1b).

4.Then, looking through the viewfinder, turn some or all of the viewfinder’s alignment screws (5, Fig. 1d, also see 4 and 6, Fig 12) until the viewfinder’s crosshairs point precisely at the same object as centered in the main telescope. The viewfinder is now aligned to the main telescope. The right-hand image in Fig. 13A shows an object centered in the main telescope before the viewfinder (the left-hand image) has been aligned to the main telescope. Fig. 13B shows these same images after the viewfinder and main telescope are aligned.

5.Check this alignment on a celestial object, such as the Moon or a bright star, and make any necessary refinements.

Choosing an Eyepiece

A telescope’s eyepiece magnifies the image formed by the telescope’s main optics. Each eyepiece has a focal length, expressed in millimeters, or “mm.” The smaller the focal length, the higher the magnification. For example, an eyepiece with a focal length of 9mm has a high- er magnification than an eyepiece with a focal length of 26mm.

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